1. Field of the Invention
The present invention relates to a logic circuit using resonant-tunneling transistors which include resonant-tunneling hot electron transistors (RHETs) and resonant-tunneling bipolar transistors (RBTs). More particularly, it relates to a latch circuit, a memory cell, and a frequency dividing circuit with a simple circuit construction, a high operation speed, and an extremely stable operation.
2. Description of the Related Arts
Latch circuits, memory cells and frequency dividers using bipolar transistors and/or metal insulation semiconductor (MIS) transistors have been extensively used for many years. In the prior art, however, a practical static memory cell requires at least two conventional transistors, and practical frequency dividers require at least three conventional transistors. As a result, the prior art memory cells and frequency dividers suffer from the disadvantages of a complex circuit arrangement, and accordingly, a low integration density. These circuits also suffer from a disadvantage of a low operation speed.
Memory cells using diodes having a differential negative-resistance characteristic are also known in the prior art. These memory cells feature a simple circuit arrangement but have a poor operation stability.
Conversely, although a higher potentiality of three terminal resonant-tunneling devices have long been recognized, they cannot be realized in practice due to the difficulties involved in the relevant semiconductor processing technology. Recently, due to advances in aspects of semiconductor processing technology, such as molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD), practical resonant-tunneling transistors have been developed (e.g., "RESONANT-TUNNELING HOT ELECTRON TRANSISTORS (RHET): POTENTIAL AND APPLICATIONS", N. Yokoyama, et al., Japanese Journal of Applied Physics, Vol. 24, No. 11, November 1985, pps. L853-L854).